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What is your average shift range?

  • Under 2000 RPM

    Votes: 3 13.6%
  • 2000 - 2500 RPM

    Votes: 6 27.3%
  • 2500 - 3000 RPM

    Votes: 11 50.0%
  • 3000 - 3500 RPM

    Votes: 2 9.1%
  • 3500 - 4000 RPM

    Votes: 0 0.0%
  • Higher than 4000 RPM

    Votes: 0 0.0%

  • Total voters
    22
1 - 11 of 11 Posts

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2000 ML430 SOLD, 2007 BMW 328i Coupe, 2014 BMW i3
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Discussion Starter #1 (Edited)
So the other day, I was reading a member's post where he was speaking about how he usually goes to 2,500-3,000 RPM before he shifts. I found this interesting since under normal conditions, I try to keep mine under 2,000. This got me thinking... I realize there are going to be gearing differences between the different engines and traffic conditions, but at what range do most people shift (or their trucks shift automatically) at?

...And then I began wondering about something else. Obviously allowing the engine to rev very high will consume more gas, but has anyone found the inverse to be true - that driving too soft/shifting too early causes a drop in fuel efficiency?

Discuss amongst yourselves.
 

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Purple Moderator
99 ML430, 00 ML320, 05 E500 4matic Wagon
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Because of the hilly terrain I am in it is around 3,000 just during normal driving.
 

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11,243 Posts
My average shift point was between 2500-3000rpm on a normal day. If I ever needed to get ahead of traffic it was either WOT or I would have it shift at around 4000rpm. Second gear pulls hard beyond 3800rpm. On a slow day, or when I was really relaxed (like late night) I would be very easy on the gas and let it shift at 2000rpm.
 

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03 ML350
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245 Posts
... Obviously allowing the engine to rev very high will consume more gas, ...
Not that you put a number on high, but I don't think 3000 rpm is high at all for an engine that easily turns over 6000 rpm. Highway cruise rpm is up in that range anyway.

I also don't buy the public perception, fueled by 15 second spots from money saving gurus on morning talk shows, that extremely low acceleration rates conserve gas. First, there's the obvious conclusion that getting stopped at lights wastes gas. Energy lost in braking is not recovered without regenerative systems. If lights are missed by a couple seconds because the driver wanted to go easy on the accelerator pedal, then gas was wasted. And, don't forget about all the people behind who couldn't make the light even if the putz just squeaked through. Similar logic applies on the approach to stop lights. I'm constantly missing green left arrows because of people running extreme following distances and coasting up to lights. Even if the the light is red, often there are smart sensors in the lanes that you need to be over at the right time to trip a turn light or you will have to wait another whole cycle.

Second, instantaneous mileage sucks during any acceleration event. Is it really better to spend 1/2 a mile getting to 45 mph just to get 8 mpg instead of 5? Or is it better to get up to speed quicker, burning a little more gas early on, but driving a much farther distance in top gear with the torque converter locked up.

There is some basic physics supporting the second case. It is a fact that rolling resistance decreases with speed. The exact number will vary by vehicle and tire choice, but there is an optimum speed of travel where aerodynamic drag has increased to the point that the rolling resistance is no longer the driving factor and the least energy is consumed. I have read in the past that's it's generally around 40 mph. If you are eventually going to the same speed then you have the same kinetic energy hump to get over no matter what the rate of acceleration. Traveling the optimal speed for the entire distant will cost the least steady-state energy. Then it's down to engine and transmission efficiencies. Certainly we know that hyper-mileage cars run their engines in short burst and coast cycles. We can't shut down like hyper mileage cars or hybrids, but I don't think is should be automatically concluded that accelerating slowly is best.

Years ago I drove Saabs and the factory recommendation for best mileage on stick shifts was 1-3-5 shifting using 3/4 throttle and shifting as soon as reasonable. That meant higher revs to make the 1 - 3 and 3 - 5 jumps. GM even enforced skipping gears via gate lockouts on some manual Corvettes. Similar techniques are also required to get benefit from hybrids and cylinder de-activation. My parents have both an Escape and full-size GM Sierra. On the Escape the engine always runs until you get to ease off for steady speed and it transitions to electric. On the Sierra it stays in V8 until you get to cruise speed. Drive like a putz and they never go into electric or 4 cyl mode around town.

I'd love to see an unbiased, scientific test to see what the impact of different acceleration rates is on overall mileage on a wide variety of vehicles. The political style group-think where repeating something often enough determines whether it's a fact or not infuriates me. Show me the numbers, raw preferably, so I can draw my own conclusion. It's sad that any time I try and research something emissions or energy related that I find better data and analysis back in the 70's than now. Everything has to be dumbed down or manipulated for some other agenda today. And even if there is a slight advantage to lower rates, what is the cost? Missing lights for all the slow pokes can easily cost be 15 minutes each way on my commute. If an extra 2 gallons of gas returns 10 hours of my life a month it's worth it. Not to mention the safety of vehicle separation, better traffic flow, and courtesy for other drivers behind.
 

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2002 ML55 AMG, 2005 Chrysler Crossfire Coupe Limited, 1999 C280
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4,714 Posts
I'm pretty much the same as asianml and Mike.

I do indulge in the occasional WOT AMG moment though! :p

ps.

I have made a firm commitment with myself NEVER to look at my fuel gauge or ascertain HOW much fuel I'm consuming; to this end I have my trip computer switched permanently OFF - It's depressing to watch it otherwise! :crybaby2:
 

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05 ML500 SE
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I'm pretty much the same as asianml and Mike.

I do indulge in the occasional WOT AMG moment though! :p

ps.

I have made a firm commitment with myself NEVER to look at my fuel gauge or ascertain HOW much fuel I'm consuming; to this end I have my trip computer switched permanently OFF - It's depressing to watch it otherwise! :crybaby2:
I make it a policy not to look at the real time fuel readout.. my foot is heavy and i dont think I can make it change. It might kick my ass.
 

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2000 ML430 SOLD, 2007 BMW 328i Coupe, 2014 BMW i3
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2,982 Posts
Discussion Starter #8
This has all been very interesting thus far. I'm honestly quite surprised at the poll numbers right now... didn't expect so many 2500-3000's out there. I almost wish I had broken it up by V6 and V8s to see how that is influencing things.

@benzml350: You're right, 3000 isn't what I was referring to as high... maybe 4000. However I do think that anything over 3k and you might start losing fuel efficiency. I agree with point 1, creative driving to keep forward momentum going is always worth it in the long run (and more considerate to other drivers). Point 2 was something that I was pondering when I started this thread, however I have a sneaking suspicion that somehow it doesn't work that way. I'm going to try testing it out when I'm out late one night with no traffic to mess with my results. Will it be scientific and conclusive? Hardly! But it's better than just theorizing behind a computer all day.

@FAR: What fun would a commute be without one good WOT moment? That's what I love about these trucks - they drive quite civil most of the time, but when you hit that kickdown switch, they know what to do.
 

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03 ML350
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245 Posts
...I'm going to try testing it out when I'm out late one night with no traffic to mess with my results. Will it be scientific and conclusive...
I haven't been impressed with the fuel computer in mine. I can't decipher what the algorithm is. It seems to be an average over a relatively small window of miles but it doesn't make sense sometimes. I can be on the highway reading 24 mph average for a long distance and when I get off to find a gas station or restaurant it drops 3-4 mpg within a couple miles. But it takes many more miles for the average to come back up after I get back on the freeway. In the winter I can leave it idle for several minutes to warm it up or while I run into a store and the average barely moves. A scan gauge would be better but I'm not going to spend that much just to find out.
 

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2000 ML430 SOLD, 2007 BMW 328i Coupe, 2014 BMW i3
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2,982 Posts
Discussion Starter #10
Interesting, just reading this about the 2012 C63 AMG's transmission...

The AMG SPEEDSHIFT MCT 7-speed sports transmission impresses with its exceptional flexibility: with four driving modes as well as rev-matching and RACE START functions, it delivers comfortable shifts around town as well as instant response in high performance driving situations. The Controlled Efficiency “C” mode is programmed to provide smooth, comfortable upshifts while maintaining the lowest possible engine speed to help maximize fuel efficiency. The “S”, “S+” and “M” modes deliver increased agility through fast, responsive gear changes and higher revs. Gear changes in the “S+” and “M” modes take just 0.1 seconds.
 

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Purple Moderator
99 ML430, 00 ML320, 05 E500 4matic Wagon
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21,801 Posts
I can tell you after having driven one that it is amazing for an automatic. MB also claims
that it delivers fuel economy than a manual trans could deliver.

Forgot to mention it won the Popular Science award in 2008.
 
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